Fix empty thumbnail/icon by re-fetching data from cache

Request data for all tasks in `TasksRepository` to prevent stale data. This ensures thumbnails and icons are not replaced and become null due to race conditions. The updated code requests data for all tasks, leveraging the cache for immediate returns.

Fix: 394384233
Flag: com.android.launcher3.enable_overview_icon_menu
Test: OverviewImageTest
Change-Id: I356de13b5e9671f50bb1c2680b54b78478fadc28